“Environmental protection legislation protects communities and the environment. Breaking these rules can result in serious penalties and is an offence the ministry takes very seriously,” Environment Minister Jim Bradley said in a release.

The fine, which included a victim surcharge of $37,500, must be paid within 90 days.

The ministry and company have agreed a mistake by contractors removing scaffolding from a room in the Coronation Drive plant on Nov. 3, 2010 led to the accident when they tripped an electrical breaker, causing an oil-based feedstock to mix with a fuming sulfuric acid.

A computerized system meant to detect this failed to shut the system down. The ministry has said it is satisfied the company has taken steps to prevent such an accident happening again.

The acid release saw the first emergency use of warning sirens in the Toronto East CAER (Community Awareness and Emergency Response) network set up and maintained by chemical manufacturers including Chemtura in the Manse Valley area of West Hill.

Some residents and the principals of two local schools, however, said sirens signalling people to take shelter in buildings were not sounded quickly enough.

Kimberley Milliard, one homeowner, said the delay in sounding the siren “left our community vulnerable for an hour.”

In an email message, Milliard added the fine for the accident is “no satisfaction for our family and for our communities. We were the ones subjected to this toxic chemical and we are left with no apology and no information about the chemical concentrations we were exposed to.”

A spokesperson for Chemtura’s U.S.-based parent company could not immediately be reached for comment.